Tired of struggling to lose weight and making zero progress—despite eating a relatively healthy diet? Join the club. Yet before pure frustration inspires you trade that big salad for a bacon cheeseburger, check this out: New research shows that certain chemicals in our food—even seemingly healthy picks, such as lean meats, fish, fruits and veggies—could be encouraging your body to hang on to fat.
“These toxins—known as obesogens—disrupt the function of our hormones and others alter our gut biome, causing an imbalance of good and bad bacteria,” says Patricia Salber, MD, a board certified internist and author of the blog The Doctor Weighs In. The imbalance can lead to confused hunger cues, a sleepy metabolism, and an increase in fat cells and fat storage—all of which can lead to weight gain. “Worse, these obesogens have also been shown to increase your risk of heart disease, diabetes and high cholesterol,” says Salber.
Which means it pays to know where they’re lurking and how to steer clear of them.
Obesogen No. 1: Bisphenol-A (BPA)
Over the last few years, our increasing understanding of the dangers of this synthetic compound (found predominantly in plastic food and drink containers) has launched a new market for BPA-free bottles. That’s great, but BPA is still found in virtually all people tested nationwide. In a new study published in the journal Nature, Harvard and Brown University epidemiologists compared levels of BPA in the urine of almost 1,000 U.S. women to their self-reported weight gain over a 10-year period, and the women with the highest levels of BPA reported gaining about half a pound more per year than women with the lowest levels. Other studies show that BPA may accelerate fat-cell differentiation, disrupt pancreatic functioning, and cause insulin resistance, all of which can lead to obesity.
Steer clear: In addition to buying those BPA-free baby bottles and food storage containers, avoid plastics marked with the #7 in the recycling triangle (a surefire sign it contains BPA) and canned foods, such as canned tomatoes and tuna fish. In fact, canned tuna is one of the most BPA-laden foods on store shelves. (Also be wary of BPA-free plastic; learn more here.)
Obesogen No. 2: Triflumizole
If you tend to choose conventional over organic produce due to availability and affordability, here’s some news that may inspire you to make a different choice: A study published in the journal Environmental Health Perspectives has linked triflumizole—a fungicide commonly used on many food crops, especially leafy greens—to weight gain. When pregnant mice ingested tiny doses of triflumizole, they gave birth to babies that were more prone to obesity, and the researchers chalked it up to the fungicide acting as obesogen in the body. “Almost all of the common chemicals used on our crops are endocrine-disrupting,” says Salber, “which means they promote fat storage and undermine our body’s ability to build lean muscle.”
Steer clear: Opt for organic fruits and veggies. Yes, they can be more expensive and tougher to find than conventional produce, but here’s some more evidence that could make the extra effort and expense worth your while: Research published in the journal Environmental Health Perspectives shows that it takes just five days of eating organic fruits and veggies—or avoiding the most contaminated conventional ones—to reduce pesticide-based obesogens to undetectable levels. For a list of produce with the most pesticide residues, take a look at “The 14 Kinds of Produce With the Highest Levels of Pesticides.”
Obesogen No. 3: Emulsifiers
These chemicals are added to processed foods to improve texture and prevent separation (think of mayonnaise and salad dressings), but a new study published in the journal Naturefound they negatively impact your gut biome, creating a bacterial imbalance that can lead to metabolic syndrome. Researchers at Georgia State University fed mice emulsifiers at levels that are present in our food, and not only did it trigger obesity in the animals, but also gut diseases, such as colitis (an inflammation of the lining of the colon that can cause abdominal pain and diarrhea).
Steer clear: Since emulsifiers are found in many processed foods (and hide out as “polysorbates” and “sorbitan monostearate” on food labels), try to avoid them and load your diet with whole foods instead. “Emulsifiers are everywhere,” says Salber, “which means you can take a really great food like artichokes, which benefits your microbiome, and dip it in a mayo-based sauce that totally undoes all of the benefits,” she says. (Learn more about emulsifiers and how you can avoid them with The Sneaky Food Ingredient That Could Be Making You Fat.)
Obesogen No. 4: Antibiotics and Hormones
When cattle and other livestock are treated with antibiotics and hormones, you get a dose when eat the meat from these animals—and research shows these substances can lead to weight gain. In one study, New York University researchers found that mice exposed to comparable amounts of antibiotics had decreased levels of T-cells, which not only impairs immune function but has also been associated with obesity. Another study in the International Journal of Obesity found that the use of steroid hormones in conventional dairy farming and meat production could be a contributor to the obesity epidemic.
Steer clear: Choose antibiotic- and hormone-free meats and dairy products (look for “organic,” “free range” and “grass-fed” on the label) and choose leaner cuts of meat: Many obesogens are fat soluable, which means they’re more likely to accumulate in fatty tissues.
Obesogen No. 5: Perfluoroctanoic acid (PFOA)
Found in non-stick cookware (and sometimes referred to as Teflon), PFOA has been linked to obesity. When Danish researchers measured levels of PFOA in pregnant mothers and then compared those with their children’s body weights 20 years later, the moms who’d had the highest levels of the chemical in their blood were three times as likely to have overweight or obese daughters than mothers with the lowest levels. (The same weight gain didn’t occur in sons.) And here’s a surprise: PFOA is also found in greaseproof food wrappers and microwavable popcorn bags, which means you may be ingesting some of this chemical even if you’re a cast iron skillet devotee.
Steer clear: There’s no need to ditch your set of (expensive!) non-stick cookware. However, when you start to see chips or scratches, replace the pan—preferably with untreated stainless steel or cast iron (which has the added benefit of giving your food an boost of iron).